Dependence of the direct ionization (top panels) and excitation-autoionization rates (bottom panels) from C II → C III (left) and C III → C IV (right) at three different electron densities, log(n_e [cm⁻³]) = 7, 9, and 11. The different colours correspond to different distributions, as indicated. The bottom right panel only shows the autoionization rate for κ = 2, 5, and Maxwellian for increased clarity (κ = 3 and 10 are omitted).